The problem associated with the generation of static electricity on various objects such as electronic components, paper products, photographic film, plastics, and the like is well known.
A number of solutions directed to this problem have been proposed. In one approach, a stream of ionized air is directed towards the surface to dispel the static charge and various devices to produce such a stream have been described for this purpose. Most of these devices employ one or more electrodes disposed in proximity to either a surface of opposed polarity or a ground so as to establish an electrical field. Air then is passed through this field, becomes ionized, and is directed towards the surface carrying the static charge.
U.S. Pat. No. 3,054,553 to White discloses an electrostatic blower apparatus in which a field is created by a voltage gradient between a field electrode and a corona discharge electrode.
U.S. Pat. No. 3,137,806 to Schweriner discloses a dustproof static eliminator in which a field is created between a needle and flat surface.
U.S. Pat. No. 3,156,847 to Schweriner discloses an ionizing air gun in which the ionizing field is set up by voltage differential between a needle and metal tip.
U.S. Pat. No. 3,283,209 to Schutz discloses a static eliminator in which the outer casing is grounded.
U.S. Pat. No. 3,611,030 to Herbert discloses an ionizing apparatus in which a conductive sleeve is disposed about an electrode.
U.S. Pat. No. 3,619,719 to Waller et al. discloses a static eliminator in which voltage is applied across an electrode and a metal surface hidden from the electrode.
U.S. Pat. No. 3,643,128 to Testone discloses an ionized air projector utilizing a grounded conductive tube.
U.S. Pat. No. 4,139,879 to Laws discloses an air ionization instrument in which a field is created between a needle and a flat plate.
U.S. Pat. No. 4,194,232 to Cumming et al. discloses an ion treatment of photographic film.
U.S. Pat. No. 4,449,159 to Schwab et al. discloses an electrostatic precipitator in which a high voltage is applied between an anode and a cathode.
One problem associated with such configurations is the internal arcing which tends to occur, thereby leading to erosion and malfunction of the device. To avoid internal arcing, the distance between the electrode and the surface of opposed polarity or a ground must be sufficiently great, the voltage must be reduced, and/or the power supply must be capacitance-coupled, each of which reduces the intensity of the ionization.
A second problem with such devices involves the attraction of dirt and dust to the surface of opposed polarity or a ground, eventually leading to malfunction or preventative shutdown for cleaning.
Finally, these devices tend to be expensive to fabricate.